1. Field of the Invention
The present invention relates to a wire connection structure and an electrical connector with a cable.
2. Description of the Related Art
Recently, a bonding agent or anisotropic conductive material is widely used to connect cables for electronics equipment. An example of the anisotropic conductive material is an anisotropic conductive film. As JP 2003-176473 shows, the anisotropic conductive film is made by dispersing conductive particles and hardening and other additional agents in an epoxy resin. In use, the anisotropic conductive film is provided between two cables and heated and pressed in a high temperature atmosphere. The conductive particles are brought into close contact with each other in the film area under the pressure so that the portions of the cables are electrically connected through the conductive particles in the film area. Another example of the anisotropic conductive material is an anisotropic conductive paste.
The non-conductive bonding materials include a non-conductive film and paste. The non-conductive bonding material is locally eliminated by the pressure between two cables so that the two cables are connected directly.
For example, the anisotropic conductive film is provided on a terminal and the core wire of a cable is provided on the film, and the core wire is pressed against the terminal in a high temperature atmosphere for connection. In this method, however, the core wire is held only by the contact surface of the anisotropic conductive film so that the core wire tends to fall. In addition, part of the conductive particles escape to opposite sides of the core wire under the pressure so that the number of closely contact conductive particles becomes so low that the electrical property becomes unstable. Moreover, the core wire is exposed, coming in accidental contact with other objects.
An electrical connector with cables includes a housing for plugging with a mating connector and a plurality of terminals arranged in the housing. The connection section of a terminal is soldered to the core wire of a cable and, upon plugging, the contact section is brought into contact with the terminal of a mating connector. Alternatively, the connection section of a terminal is provided on the connection pad of a circuit board for connection to a mating connector.
JP 2004-63373 discloses a connector using a circuit board to which very thin coaxial cables are connected. In general, the core wire of a coaxial cable is soldered to the connection pad of a circuit board. Recently, there is a demand for thin coaxial cables and a small pitch with which the coaxial cables are arranged for small size, light weight electronic devices. When the thin coaxial cables are soldered with a pitch of no more than 0.4 mm, the adjacent terminals tend to be bridged with the solder, causing short circuit.
In order to solve such a problem, a jig is provided on the central conductors of thin coaxial cables on the connection pads and a laser is irradiated through the jig to connect the central conductors to the pads and, then, the laser is irradiated again to cut the pads between the central conductors.
The above method, however, requires not only the special jig through which a laser is irradiated but also the two doses of laser irradiation for melting solder and cutting the pad. If the diameter of central conductors or the number of cables is changed, another jig is required.